Bicycles with a belt drive instead of a chain drive are well known. For example, U.S. Pat. No. 4,119,326 to John F. Porter issued Oct. 10, 1978, and entitled Variable Speed Bicycle, teaches a bicycle power train comprising variable speed pulleys and a belt. This patent has a single raceway for the pulley driven by the pedals and a single raceway for the driven pulley that rotates with the rear wheel. The widths of these raceways vary in order to change the speed of the bicycle.